Field of the Invention
The invention relates in general to signal processing in a display apparatus, and more particularly to an impulsive interference detection circuit applied to a display apparatus and an associated signal processing method.
Description of the Related Art
In the Digital Video Broadcasting—Second Generation Terrestrial (DVB-T2) standard, impulsive interference is regarded as an issue that severely affects image display. Impulsive interference has large sudden and periodical amplitudes, and is usually generated by factors in the ambient environment, e.g., an operating washing machine or dishwasher, and a fast automobile passing by. FIG. 1 shows a schematic diagram of impulsive interference. In FIG. 1, the impulsive interference includes multiple burst durations having different intervals or lengths, and each of the burst durations includes one or multiple pulses. FIG. 1 depicts illustration associated with pulse cycle, pulse amplitude, pulse interval and burst interval. In the prior art, whether a received signal has impulsive interference is determined by means of detecting whether a sudden high power amplitude occurs in the signal, and signal processing of a subsequent circuit is accordingly controlled. However, for certain types of impulsive interference, the conventional detection method may result in misjudgment. For example, in the second-generation test standard announced by the Digital-TV Group (DTG), some test items have extremely long burst durations, each of which includes many pulses, e.g., one burst duration includes 400 to 40000 pulses. When the energy of such impulsive interference is strong, the conventional detection method may still successfully perform the detection. However, when the energy of such impulsive interference is weak, these test items may be overwhelmed by normal signals such that whether a received signal has impulsive interference cannot be determined simply through detecting the amplitude intensity of the received signal. In an actual application, such frequent impulsive interference with a weak strength is sufficient in affecting subsequent signal processing. Therefore, there is a need for a circuit capable of performing detection in the above situation and an associated signal processing method.